The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Simulators >> Circuit Simulators >> Is 64-bit helpful for Spectre efficiency?
https://designers-guide.org/forum/YaBB.pl?num=1218693116

Message started by Terence on Aug 13^th, 2008, 10:51pm

Title: Is 64-bit helpful for Spectre efficiency?
Post by Terence on Aug 13^th, 2008, 10:51pm

Hi all,

I am considering to upgrade our Linux from 32 to 64-bit. Our platform is Cadence Virtuoso. Does anyone have experience if 64-bit is helpful for Spectre/SpectreRF efficiency? Thanks!

Regards,
Terence

Title: Re: Is 64-bit helpful for Spectre efficiency?
Post by bernd on Aug 14^th, 2008, 2:57am

With a 32 bit CPU you have a limited memory addressing to 4GB,
which you have not with a 64 bit CPU.
The 64 bit CPU helps you for Spectre/RF if you doing memory expensive
analysis, like PSS or QPSS.

Don't forget to set the Cadence DFII environment variable 'CDS_AUTO_64BIT'
to your required value.

*

Title: Re: Is 64-bit helpful for Spectre efficiency?
Post by Terence on Aug 14^th, 2008, 6:11pm

Hi Bernd,
Thanks for your reply. Is your overall Cadence Virtuoso platform running smooth with 64-bit? Thanks!!!

Regards,
Terence

Title: Re: Is 64-bit helpful for Spectre efficiency?
Post by bernd on Aug 18^th, 2008, 4:51am

In principle yes.
There are a few exceptions like CDL in/out, the hierarchy editor and
AMS designer which we have issues with 64bit.
For some you can use the UNIX env. variable with the exclude setting (CDS_AUTO_64BIT=EXCLUDE:<TOOL>)
But this I guess is also dependent on the version of Cadence DFII you use.

*